What is involved in the knee jerk reflex

knee-jerk reflex, also called patellar reflex, sudden kicking movement of the lower leg in response to a sharp tap on the patellar tendon, which lies just below the kneecap. … The sharp tap on the tendon slightly stretches the quadriceps, the complex of muscles at the front of the upper leg.

Which nerve is responsible for patellar reflex?

The axon enters the spinal cord via the dorsal nerve root. The spinal cord segments are L4-5(6). The axon travels into the ventral grey matter and stimulates the alpha motor neuron. The axons of these neurons travel in the femoral nerve and cause contraction of contraction of quadriceps muscle and extension of stifle.

Is interneurons involved in knee jerk reflex?

The monosynaptic knee-jerk reflex skips the interneuron, so it involves the sensor, sensory neuron, motor neuron, and muscle fiber (Figure 2).

What nerve is carrying afferent and efferent nerve impulses?

Due to their function, nerve fibers which carry afferent impulses are known as afferent nerves or sensory nerves, and those nerve fibers which carry efferent impulses are known as efferent nerves or motor nerves.

Which of the following is not involved in knee jerk reflex?

Brain is not involved in any reflex action (e.g., knee-jerk reflex) while the muscle spindle, inter neuron and motor neuron are the part of reflex arch.

Which nerve carries impulses to the CNS?

Cranial nerves, spinal nerves, and ganglia make up the peripheral nervous system. The afferent division of the peripheral nervous system carries impulses to the CNS; the efferent division carries impulses away from the CNS.

What part of nervous system controls reflexes?

The part of the brain that controls reflexes is the cerebellum. The cerebellum regulates motor reflexes and is also involved in the synchronization of balance and muscles. The brainstem links and transmits messages to the spinal cord from the brain, regulating functions such as respiration, heart rate, and alertness.

Which neuron carries nerve impulses towards its cell body?

A typical neuron has a cell body containing a nucleus, one or more branching filaments called dendrites which conduct nerve impulses towards the cell body and one long fibre, an axon, that carries the impulses away from it.

Are most nerves motor nerves?

Most of the nerves have both sensory and motor components. Three of the nerves are associated with the special senses of smell, vision, hearing, and equilibrium and have only sensory fibers. Five other nerves are primarily motor in function but do have some sensory fibers for proprioception.

How does the nervous system respond to kicking the ball?

Sensory nerves carry messages from receptors to the brain. If you touch a hot iron, pain receptors tell your brain to move your hand. Motor nerves send signals from the brain to the muscles in the body. These nerves help us to do things such as walk, kick a ball or pick up an object.

Article first time published on

Which of the following is not involved in a reflex response?

The correct answer is Movement of hand. Breathing, Heart-pumping, Salivation, Blinking of eyelids etc. is a reflex action. Movement of hand is can be both voluntary and involuntary. Hence it can’t be a strictly reflex action.

Which one is not a reflex action?

Sweating is not a reflex action. It is primarily a means of temperature regulation. But, salivation on seeing food, hand withdrawal because of the needle and blinking of the eyes due to bright light are all examples of reflex actions.

Is knee jerk somatic or autonomic?

Autonomic Reflexes Activity 1- Patellar reflex The patellar tendon reflex or knee-jerk reflex is a monosynaptic stretch reflex that assesses the nervous tissue between (and including) the L2 and L4 segments. It can be done by tapping the patellar ligament (just below the knee) with a reflex hammer.

Where do the motor nerves carry impulses?

Sensory neurons carry nerve impulses from sense organs and internal organs to the central nervous system. Motor neurons carry nerve impulses from the central nervous system to organs, glands, and muscles—the opposite direction.

Where do nerve impulses for movement generate?

The place where an axon terminal meets another cell is called a synapse. This is where the transmission of a nerve impulse to another cell occurs. The cell that sends the nerve impulse is called the presynaptic cell, and the cell that receives the nerve impulse is called the postsynaptic cell.

What passes nerve impulses between the brain and spinal cord?

Sensory neurons transmit nerve impulses from sense organs (eyes, ears, nose, tongue and touch) to the brain. They also carry nerve impulses to the brain and spinal cord. Motor neurons transmit nerve impulses from the brain and spinal cord to a specific area of the body.

What is sensory nerve and motor nerve?

Afferent nerve fibers in a sensory nerve carry sensory information toward the central nervous system (CNS) from different sensory receptors of sensory neurons in the peripheral nervous system. … A motor nerve carries information from the CNS to the PNS, and both types of nerve are called peripheral nerves.

Which type of nerve are motor neurons?

Motor neurons are a specialized type of brain cell called neurons located within the spinal cord and the brain. They come in two main subtypes, namely the upper motor neurons and the lower motor neurons. The upper motor neurons originate in the brain and travel downward to connect with the lower motor neurons.

Where is the motor nerve?

A motor nerve is a nerve located in the central nervous system (CNS), usually the spinal cord, that sends motor signals from the CNS to the muscles of the body. This is different from the motor neuron, which includes a cell body and branching of dendrites, while the nerve is made up of a bundle of axons.

What is multipolar neuron?

A multipolar neuron is a type of neuron that possesses a single axon and many dendrites (and dendritic branches), allowing for the integration of a great deal of information from other neurons. These processes are projections from the neuron cell body.

What is Soma in neuron?

Soma. The soma, or cell body, is where the signals from the dendrites are joined and passed on. The soma and the nucleus do not play an active role in the transmission of the neural signal. Instead, these two structures serve to maintain the cell and keep the neuron functional.

Which subdivision of the nervous system is considered involuntary?

It is further subdivided into sympathetic and parasympathetic divisions. Because the autonomic nervous system regulates involuntary or automatic functions, it is called the involuntary nervous system.

What are spinal nerve plexuses?

A nerve plexus is a network of intersecting nerves; multiple nerve plexuses exist in the body. Nerve plexuses are composed of afferent and efferent fibers that arise from the merging of the anterior rami of spinal nerves and blood vessels.

Which part of the nervous system is not involved in producing reflex actions?

All reflex actions follow an overall sequence through the nervous system which is called the reflex arc. Crucially this does not involve the conscious part of the brain, which makes it much quicker.

Which are nerve plexuses of the body?

Cervical plexus – serves the head, neck and shoulders.
Brachial plexus – serves the chest, shoulders, arms and hands.
Lumbosacral plexus. Lumbar plexus – serves the back, abdomen, groin, thighs, knees, and calves. …
Coccygeal plexus – serves a small region over the coccyx.

Is breathing a reflex?

Anoxemia may produce its relatively rapid breathing by augmenting this function. The present experiments indicate the great importance of reflexes and their modification through chemical changes and suggest the breathing may be fundamentally a reflex phenomena.

Is shivering a reflex action?

When the core body temperature drops, the shivering reflex is triggered to maintain homeostasis. Skeletal muscles begin to shake in small movements, creating warmth by expending energy. Shivering can also be a response to a fever, as a person may feel cold.

Is weeping a reflex?

This type of tear is made in the lacrimal gland and is made up mostly of water. The body makes these tears as a reflex to a stimulus. For example: if a bug flies into your eye the eye tears to flush out the bug.

Why are association neurons involved in reflex arcs?

Reflex arcs Sensory neuron sends electrical impulses to a relay neuron, which is located in the spinal cord of the CNS. Relay neurons connect sensory neurons to motor neurons. Motor neuron sends electrical impulses to an effector. Effector produces a response (muscle contracts to move hand away).